Drums provide a mechanism by which materials, such as solids and/or liquids are housed. The housing may be for a limited duration, or, as in the case of nuclear waste storage, for extended time periods, up to and often exceeding years in duration. The drums have drum closures which allow the entire drum unit (i.e. the drum body and lids) to be sealed in order to prevent spilling or escape of drum contents.
Drums come in various sizes, such as, for example, 55 gallon capacities. Under conditions where the interior contents are not volatile and the drum is not moved, the drum is sealed by placing a lid on a lip of the drum body. The lid is then press fitted into the opening of the drum body. This type of seal is economical to produce, however, the resulting connection between the drum body and the lid is not structurally rugged. During a tipping of the drum, contents may escape as the body and lid may separate. If the drum is subjected to an accident, such as dropping the drum from a height of thirty (30) feet, the drum and lid separate causing the contents to exit the drum.
To prevent escape of drum contents, in the exemplary case of a hazardous material drum, drum closures attempt to seal the drum body and lid into a single unit, thereby preventing escape of drum contents. Such drum closures may be configured as split closure rings which attempt to fasten the lid to the drum head through tightening lugs which compress the ends of the rings together. These closures, however, have been found to be inadequate for accident scenarios postulated for drum designs for use in, for example, nuclear material storage. Due to changing regulations regarding postulated accident scenarios for this type of storage, these drum closures must now be designed and configured to withstand both postulated puncture type accidents and high elevation drop accidents. Although structurally superior to standard drum closures, the current hazardous material drum closure designs still do not provide sufficient closure strength for severe accidents including puncture and dropping the drum from thirty (30) feet.
There is a need for a drum closure design and configuration which will withstand severe accident forces and prevent drum contents from spilling or escaping from the drum.
There is a further need for the drum closure to be economical and easily installed on existing drum designs.
There is a further need for the drum closure to resist puncture accidents as well as blunt impact accidents.